This NASA Hubble Space Telescope image reveals how wave-like structures unleashed by the powerful remnant of a dead star move outward over time in the heart of the Crab Nebula.

The surviving remnant is the collapsed core of a burned-out star, and is called a neutron star. This powerhouse has about the same mass as the sun but is squeezed into an ultra-dense sphere that is only a few miles across and 100 billion times stronger than steel. It is a tremendous dynamo, spinning 30 times a second. This whirling dynamo is visible in the image as the bright object just below center. The object to the left of the neutron star is a foreground or background star.

The image was assembled from three separate exposures taken between September and November 2005 by Hubble's Advanced Camera for Surveys. Each epoch was assigned a different color to show the motion of the wave-like features over time.